Interesting. The linked Wikipedia article talks about speaking and reading, and the later is indeed way harder to learn in asian languages. It would be interesting to see how this list turned out if you ignore the reading/writing. In Japanese, you can also write everything in Hiragana, for example; that's easy to learn but not as exact due to homonyms, words that are pronounced the same but have different meaning. These words usually have different Kanji, so you can distinguish them when using Kanji but not when using Hiragana. My experience is this: I'm German, have learned English and French at school (though I can't talk the later now) and have learned Japanese in an evening school (though I can't speak that one either now). I found that while Japanese has a totally different grammar than the others, it was easier to learn due to the grammar being not as complex and not having so many exceptions like european languages usually do (irregular verbs and the like). But it seems I'm the exception here.